Radial arm saw safety top

ABSTRACT

A radial arm saw is adapted with a safety top configured with cutting box enclosure that contains and collects substantially all of the sawdust generated during use. A dust collection system is in fluid communication with the cutting box for removing the sawdust contained therein. Spring biased push blocks function to hold the work piece in place during the sawing process while maintaining the user&#39;s hands safely away from the saw blade. A laser alignment device projects a beam within the cutting box along the cutting plane. A control panel is provided to allow use by authorized users upon entry of an authorization code.

CROSS REFERENCE TO RELATED APPLICATIONS

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STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

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COPYRIGHT NOTICE

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BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to radial arm saws, and more particularlyto a safety top for use in safe operation of radial arm saws whileproviding improved dust collection.

2. Description of Related Art

Radial arm saws are routinely found in wood working environments for useus in various wood cutting applications. Over the past several years,the use of the radial arm saw has expanded significantly due largely toversatility and simplicity of use. Today, radial arm saws are in use inwood working shops, garages, even retail outlets, such as hardware andhome improvement stores.

A typical radial arm saw includes a work table having a horizontal flattop work surface with a vertically projecting backstop, commonlyreferred to as a fence. The material to be cut, such as a piece of wood,is supported on the work surface and against the fence. At the rear ofthe work table a vertical column extends upwardly. Extendinghorizontally from the top of the column is a radial arm, which iscapable of rotation about the column, but which is generally positionedover the top of the table. A rotary power saw is suspended below theradial arm by a carriage adapted for travel along the length of theradial arm. In most operations, the saw is positioned over the worktable and is moved along the radial arm to cut a workpiece positioned onthe work surface.

While the radial arm saw is an efficient and proven power tool, thereremain a number of problems and shortcomings associated with theoperation thereof that heretofore have not been adequately solved oraddressed. One such problem associated with the radial saw operationrelates to the substantial amount of sawdust created and dispersed whencutting. The sawdust generated by a radial arm saw ranges from very finedust particles to larger wood chips. While this problem has been widelyrecognized for many years, radial arm saw manufacturers have failed todevelop an effective dust collection system for use with these saws. Onecommon, yet ineffective, solution has been to provide the saw blade witha protective guard or hood adapted with a suction port connected to avacuum-generating dust collection system by a hose. That attempt,however, has proven unsatisfactory and generally ineffective.

As a result of the persistent problems associated with saw dust, thebackground art reveals a number of attempts directed to dust collectionsystems for use with radial arm saws. For example, U.S. Pat. No.2,839,102, issued to Kido, discloses a dust collecting attachment thatmounts behind the guide fence of a radial arm saw. The attachmentdefines slotted openings aligned with kerfs in the guide fence, and isattached to a suction-generating dust collector apparatus. U.S. Pat. No.3,322,169, issued to Hilliard, discloses a dust collector for a radialarm saw including a rectangular shroud having an inlet and a taperedtube extending rearwardly therefrom for connection to a vacuum hose.U.S. Pat. No. 3,401,724, issued to Kreitz, discloses a dust collectorfor a radial arm saw comprising generally funnel-shaped hood positionedat the rear of the work table. The wide hood inlet opens toward thefront of the work table and a narrow outlet is connected to a dustcollector apparatus. U.S. Pat. No. 4,144,781, issued to Kreitz,discloses a dust collector for a radial arm saw including a generallyfunnel-shaped flat-bottomed shroud connected to a vacuum hose. The topand bottom of the shroud are contoured so that the shroud partiallysurrounds the column which supports the radial arm saw. U.S. Pat. No.4,742,743, issued to Scarpone, discloses a radial arm saw accessorycomprising a grid structure formed in the table surface in proximity tothe fence to permit passage of sawdust therethrough.

It appears, however, that the above-referenced advances in the art ofradial arm saw dust collection have not been successful in substantiallycontaining and collecting sawdust generated by the radial arm saw.Accordingly, those devices have not gained widespread acceptance. Thus,there exists a need for improvements in radial arm saw design. Moreparticularly, there exists a need for an improved dust collection systemfor use with radial arm saws.

Another serious problem present with the widespread use of radial armsaws relates to operator safety. More particularly, during normal usethe rotating saw blade often comes in close proximity to the operatorshands and fingers. As a result, numerous individuals have been seriouslyinjured by inadvertent contact with the rotating saw blade whileoperating the radial arm saw. The problem is complicated since operationof the saw requires the user to move the saw/blade across the worksurface while cutting thereby increasing the risk of injury. The risk ofinjury increases when the saw is used by inexperienced operators ingarage shops or employees in retail locations. Despite the serious riskof injury inherent with conventional radial arm saw designs,manufacturers have failed to provide adequate measures intended toprevent injury.

The background art reveals a number of attempts directed to protectingoperators from injury while operating radial arm saws. These attemptsinclude blade guards intended to prevent the operator's hand fromcontacting the rotating blade. Blade guards, however, have provenineffective. Other attempts include providing work piece guides and pushdevices designed to assist the operator in positioning the work piece.U.S. Pat. No. 5,678,467, issued to Aigner, discloses a handle adaptedfor holding or pushing wood during the sawing process. The Aignerdevice, and others in the art, provide handle-like structures thatengage the wooden workpiece such that the user's hand is positioned awayfrom the cutting plane. The prior art further reveals a number of workpiece guides, primarily for use with table saws. Representativedisclosures of such devices are found in U.S. Pat. Nos. 4,026,173(Livick), 4,469,318 (Slavic), and 4,485,711 (Schnell). These devices,however, are adapted for pushing and guiding the workpiece though thecutting area, and are generally not suitable for use with a radial armsaw wherein the saw blade is moved through the workpiece. Accordingly,there exists a need for improvements directed to radial arm sawsdirected to protecting operators from injury by securing the workpiece.

BRIEF SUMMARY OF THE INVENTION

The present invention overcomes the disadvantages and shortcomings inthe art by adapting a radial arm saw with a safety top configured with acutting box enclosure for containing and collecting substantially all ofthe sawdust generated when in use. The safety top further includesspring biased push blocks that function to hold the work piece in placeduring the sawing process while maintaining the user's hands safely awayfrom the saw blade. In accordance with the present invention, a radialarm saw is adapted with a safety top providing an improved work surface,a fully integrated structure that contains and captures substantiallyall of the sawdust and particles generated by the saw, and integratedpush blocks that are mechanically biased to secure the workpiece inengagement with the fence.

Accordingly, it is an object of the present invention to provide animproved safety top for use with radial arm saws.

Another object of the present invention is to provide an improved dustcollection system for use with radial arm saws.

Still another object of the present invention is to provide advancementsin control systems for radial arm saws.

In accordance with these and other objects, which will become apparenthereinafter, the instant invention will now be described with particularreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 depicts a typical radial arm saw of the prior art;

FIG. 2 depicts a radial arm saw adapted with a safety top in accordancewith the present invention;

FIG. 3 illustrates cutting of a wood work piece using a radial arm sawadapted with a safety top in accordance with the present invention;

FIG. 4 is a bottom view of the safety top showing alternate mechanicalbiasing systems for the push handles;

FIG. 5 is a top view of the safety top wherein the saw is positioned tocut a wood work piece;

FIG. 6 is a top view of the safety top wherein the work piece has beencut; and

FIG. 7 depicts a control panel for use with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 depicts a radial arm saw 10 typical of prior art saws to whichthe present invention most directly pertains. The typical radial arm saw10 includes a work table 20 having a horizontal flat top work surface 22with a vertically projecting backstop 24, commonly referred to as a ripfence. The material to be cut, such as a piece of wood, is supported onwork surface 22 in abutting relation with fence 24. A vertical column 30extends upwardly from the back of work table 20. Extending horizontallyfrom the top of column 30 is a radial arm 32, which is capable ofrotation about the column, but which is generally positioned over thetop of the table. A rotary power saw 40 is suspended below the radialarm by a carriage adapted for travel along the length of radial arm 32.Power saw 40 includes a rotating blade 42, a protective blade shroud 44,a motor housing 46, and a handle 48. As noted above, blade shroud 44 isoften configured to function as a dust collecting shroud by attachmentof a shop vac dust collector thereto. In most operations, the saw ispositioned over the work table and is moved along the radial arm to cuta workpiece positioned on the work surface when pulled by the user suchthat the saw moves from behind the fence through the workpiece to becut.

FIG. 2 depicts a radial arm saw adapted with a safety top assembly,generally referenced as 100, an improved control system, which includesa control panel 200, according to the present invention. Safety top 100is preferably fabricated from a durable material. In a preferredembodiment, safety top 100 is fabricated from sheets phynolic material,which sheets are known for their strength, high heat resistance andflame retardancy. It should be noted, however, that any suitablematerial is considered within the scope of the present invention. Safetytop 100 is preferably a fully assembled structure adapted for mountingdirectly on to a radial arm saw with minimal if any modificationrequired.

Safety top 100 includes a generally planar work surface 102 and abackstop or rip fence 104 (hereinafter “fence”) vertically projectingtherefrom. Work surface 102 defines a pair of slotted apertures 106 thatfunction as guide slots for push handles 108. Each push handle 108includes a base 108A, a vertical end wall 108B for engaging a workpiece,and a cutout portion 108C to facilitate grasping thereof by the user.Base 108A includes a downwardly projecting tongue sized for slidableinserted engagement with slotted aperture 106. FIG. 3 depicts a woodworkpiece, such as a two-by-four disposed between push handles 108 andrip fence 104.

Each push handle 108 is mechanically biased toward fence 104 by a springloaded biasing mechanism preferably disposed on the bottom surface ofwork surface 102. FIG. 4 shows a bottom view of safety top 100 anddiscloses a preferred helical spring loaded embodiment of the mechanicalbiasing system depicted on the right hand side of FIG. 4B, whichembodiment is generally referenced as 110, and an alternateauto-retracting embodiment mechanical biasing system depicted on theleft hand side of FIG. 4B, which embodiment is generally referenced as120. The helical spring mechanical biasing system 110 includes aplurality of anchors 112 fastened to the underside of work surface, andan anchor 114 fastened to the lower portion of push handle 108. A springbiased cable and pulley system is connected to anchors 112 and 114. Moreparticularly, the spring biased cable and pulley system includes a chainsection 116 connected at one end thereof to an anchor 112, a helicalspring 117 connected on one end thereof to chain 116 and connected atthe opposite end thereof to a first pulley 118. A cable 119 is routed ina two pulley configuration with opposing cable ends connected to a fixedanchor 112 and anchor 114 respectively thereby realizing a mechanicaladvantage. The provision of chain section 116 allows for adjustment ofthe tension by adjustable connection of individual links to anchor 112.The alternate embodiment mechanical biasing system 120 includes anautomatic retraction apparatus 122 connected to the lower portion ofpush handle 108 by a cable 124. Automatic retraction apparatus 122 isgenerally characterized as providing a retraction force of asubstantially constant level by use of internal spring mechanisms. Itshould be noted, however, that any suitable biasing system, whethermechanical or electrical is considered within the scope of the presentinvention. As should be apparent, the mechanical biasing systemsfunction to urge push handles 108 toward rip fence 104 so as to secure apiece of wood in place for the sawing process.

Safety top 100 further includes dust collecting cutting box 130 mountedon and projecting above work surface 102. Cutting box 130 is preferablymounted in alignment with power saw 40, and particularly saw blade 42for reasons more fully discussed hereinbelow. Cutting box 130 is boundedby a floor formed by the work surface 102, and further includes a top132, opposing sides 134, and front and rear walls 136. Top 132 defines aplurality of slotted apertures (“slots”), including a saw blade slot 137aligned with saw blade 42, and left and right slotted apertures 137disposed on opposing sides of blade slot 137 and in parallel relationtherewith. Saw blade slot 137 allows saw blade 42 to pass below cuttingbox top 132 during the sawing process. Left and right slotted apertures138 function to provide the user with a line of sight through cuttingbox top 132 to the cutting area disposed below. Cutting box sides 134include portions thereof formed by brush bristles 135 connected to andprojecting downwardly from top 132, extending forward from fence 104.Brush bristles 135 allow a work piece to be inserted into cutting box130 and automatically form a seal to contain saw dust within cutting box130. The present invention further contemplates providing the sawportion with a specially adapted semi-circular shroud 150 in partialcovering relation with the saw blade. Shroud 150 defines a bottomopening having a generally rectangular cross-section, which openingincludes brush bristles 152 attached to the peripheral edge thereof.Shroud bristles 152 project downwardly from shroud 150 and are insweeping contact with the cutting box top 132 thereby forming a dustseal between shroud 150 and top 132 as the saw moves back and forthwhile cutting the work piece.

Cutting box 130 thus defines an internal chamber wherein the rotatingsaw blade meets the work piece during the cutting process and functionsto contain the sawdust and wood chips generated as the blade cutsthrough the wood. Accordingly, cutting box 130 is further adapted forconnection to an external dust collection system. More particularly,cutting box 130 is adapted with first and second dust collection outletports, referenced as 160 and 162 respectively. Each outlet port providesa connection point for attachment of a hose from a vacuum generatingexternal dust collection system. Since vacuum type dust collectionsystems are well known, those systems shall not be further detailed.Outlet port 160 is preferably located rearward along cutting box side134 and thus places the interior of cutting box 130 in fluidcommunication with the external dust collection system. As best depictedin FIG. 4, second outlet port 162 is defined by a dust collecting tray164 disposed beneath work surface 102 in alignment with a slottedaperture 166 defined bottom of work surface 102. First and second outletports are preferably connected to a common dust collection system by avacuum hose adapted with a Y-fitting.

As best depicted in FIG. 3, safety top 100 further includes a flexible,generally flat, strip of sealing material 170 having a first end thereofattached to shroud 150 and a second end thereof 172 hanging or drapingdown the back side of safety top 100. Sealing strip 170 further includesopposing edges thereof riding within grooves formed on opposing sides ofsaw blade slot 137. Accordingly, as the saw is moved forward during thecutting process, sealing strip 170 is pulled in trailing relation withshroud 150 so as to cover or seal that portion of saw blade slot 137behind the saw thereby providing a seal and preventing saw dust fromescaping. As the saw is moved rearward during the cutting processsealing strip 170 is pushed rearward while traveling within groovesformed on opposing sides of saw blade slot 137. As should be apparent,any sawdust generated during operation of the radial arm saw adaptedwith a safety top 100 in accordance with the present invention will becontained within cutting box 130 and will be removed therefrom via dustcollection outlet ports 160 and 162.

As best depicted in FIGS. 5 and 6, radial arm saw safety top 102 furtherincludes a laser alignment device 180 for projecting a light beam 182over the work piece to insure proper alignment and precise cutting. In apreferred embodiment, laser alignment device 180 is mounted withincutting box 130 and oriented so as to project a light beam over the workpiece and along the cutting plane formed by the edge of the saw blade.Light beam 182 thus provides visible indication as to exactly where thesaw blade will intersect the work piece. Light beam 182 may be visibleto the operator through any of cutting box top slots 137 or 138.

As further illustrated in FIG. 2, the present invention may furtherinclude a control panel, referenced as 200 which functions to providesafe and efficient operation of the radial arm saw, particularly forsaws operating in retail store environments, such as saws operating inhome improvement and hardware stores. Control panel 200 provides aprimary connection to electrical power, such as 208VAC, 230 VAC, or460VAC electrical power and includes a step-down electrical transformercapable of 24 VAC output. The ability of control panel 200 to operateusing a range of voltages is considered important since the poweravailable at different locations often varies. Control panel 200includes a keypad 202 that provides an input device to restrictoperation to authorized users who enter an appropriate authorizationcode. A power supply is connected to the 24 VAC output for providing DCpower to keypad 202. Control panel 200 further includes a maindisconnect switch 204 that enables quick disconnection of power to thesaw and various components. In addition, a push-start/pull-stop controlbutton 206 is provided to initiate or discontinue operation. Further,control panel 200 includes a visual alarm beacon 208 that is configuredto flash when power is supplied to the radial arm saw systems, and analarm horn 210 that is configured to generate an audible sound after apredetermined time period to indicate that the radial arm saw is aboutto shut down.

The operating sequence for a radial arm saw adapted with a control panelaccording to the present invention is a follows. A red indicator light202A on the keypad indicates that power is being supplied to the radialarm saw control panel. The user enters the appropriate security code onthe keypad to initiate operation. As should be apparent, any suitablecode may be used. Upon entry of the appropriate code, a light 206A oncontrol button 206 illuminates indicating that a predetermined operationperiod, such as five minutes, has begun. The user then must pull controlbutton 206 to automatically supply power from the control panel to theradial arm saw and dust collection system, at which time beacon 208 isactivated thus providing a visual signal/warning that power has beensupplied and the systems are operational. Shortly before expiration ofthe predetermined operation period (e.g. 30 seconds prior to expiration)alarm horn 210 sounds as a signal that the saw will automatically shutdown shortly. While the system is programmed to allow operation for apredetermined period of time before automatically shutting down, theperiod of operation may be extended by re-entering the authorizationcode. If, at any time, the operator wishes to manually shut the systemsdown he simply must push control button 206.

The instant invention has been shown and described herein in what isconsidered to be the most practical and preferred embodiment. It isrecognized, however, that departures may be made therefrom within thescope of the invention and that obvious modifications will occur to aperson skilled in the art.

1. In combination with a radial arm saw assembly comprising a tablehaving a top and a rip fence projecting upward therefrom, a verticalcolumn extending upwardly near the rear of the top, a radial armextending horizontally from the top of the column, a rotary power sawsuspended below the radial arm by a carriage adapted for travel alongthe length of radial arm, the saw including a rotating blade, aprotective blade shroud, and a handle, the improvement comprising: awork surface mounted to the table top; at least one push handle inslidable engagement with said work surface for movement toward and awayfrom said rip fence; a cutting box disposed on top of the work surface,said cutting box defining an interior bounded by a top in spacedrelation with said work surface, opposing side walls, and front and rearwalls; at least one of said side walls defining an opening therein withbrush bristles disposed in said opening to allow a work piece to be atleast partially inserted within said cutting box through said opening;said cutting box top defining an elongate slotted aperture for receivingthe lower portion of the saw blade as the blade travels during thesawing process; and said cutting box interior in fluid communicationwith dust collection structure for collecting sawdust.
 2. Thecombination of claim 1, further including a laser alignment deviceprojecting a beam along said cutting box top slotted aperture toward thesaw blade.
 3. The combination of claim 1, further including saidprotective blade shroud including downwardly projecting brush bristlesconnected along a lower peripheral edge thereof, said brush bristlesengaging the top of said cutting box.
 4. A safety top for use incombination with a radial arm saw assembly comprising a table having atop, a vertical column extending upwardly near the rear of the top, aradial arm extending horizontally from an uppermost portion of thecolumn, a rotary power saw suspended below the radial arm by a carriageadapted for travel along the length of radial arm, the saw including arotating blade, a protective blade shroud, and a handle, comprising: aplanar top work surface mounted on the table top, said planar top worksurface including a rip fence extending vertically upward therefrom, andat least one push handle in slidable engagement with said top worksurface for movement toward and away from said rip fence; a cutting boxdisposed on top of the work surface, said cutting box defining aninterior bounded by a top in spaced relation with said work surface,opposing side walls, and front and rear walls; at least one of said sidewalls including an opening therein, the opening having brush bristlesdisposed therein to allow a work piece to be at least partially insertedwithin said cutting box through said opening; said cutting box topdefining an elongate slotted aperture for receiving the lower portion ofthe saw blade as the blade travels during the sawing process; and saidcutting box interior in fluid communication with dust collectionstructure for collecting sawdust.
 5. A safety top for use in combinationwith a radial arm saw assembly according to claim 4, further includingmeans for projecting a light beam toward the saw blade in alignment withsaid cutting box top slotted aperture.
 6. A safety top for use incombination with a radial arm saw assembly according to claim 4, furtherincluding a protective saw blade shroud disposed in partial coveringrelation with said saw blade, said shroud having a lower peripheral edgeportion defining an opening, said lower peripheral edge includingdownwardly projecting brush bristles in sweeping engagement with saidcutting box top.